I fukk with the Starks but, Robb fukked up breh. Your father just got his head cut off, people chose you to be the King of the North. You supposed to do everything in your power to unite those houses further and go to war with the people who destroyed your family.
Nothing else matters. Instead you alienate one house by breaking your bond, then alienate another by killing a close ally over some Lannister children, then you cause everyone to lose faith in you by letting Jamie Lannister go free (not Robb's fault but, fukk it). Then you add insult to injury by going BACK to Lord Frey to ask for help after shytting on him. Then you shyt on him further with that weak azz offer. Negro, he wanted a King for a son...not your fugazzi azz Uncle. How could you not see that, that move was disrespectful?
Then to make matters worse, the broad you didn't want to marry wasn't even ugly. She's actually attractive